1. Field of the Invention
The present invention relates to the field of the reception of video contents on mobile terminals, in particular the procedures allowing the reception of contents on request.
This application is based on and claims priority to EP 05111336.3, filed Nov. 25, 2005, the entire contents of which being hereby incorporated by reference.
2. Discussion of Background
The broadcasting servers schematically stream two types of products, those with free access and those with conditional access. For the second type, the content is encrypted by at least one encryption key. At the time of the broadcast of said encrypted content, a descriptor indicates the rights that are necessary to access this content and the enciphering key, this descriptor being called a control message (ECM). This message is processed by a security module located in the mobile terminal that comprises means to process this control message and verify if the mobile terminal disposes of the corresponding right.
Therefore, before the reception of a multimedia content, the right relative to this content must be loaded into the terminal, in particular in the security module. According to another embodiment, the right is replaced with a key that is used to decrypt the control message comprising the current decryption key of the content.
According to one conventional method, the user access a presentation service for contents related to events and selects one or more contents in which he is interested. In this method called point-to-point, a message is sent to the user, such message including the key or the right to access the event.
This message is stored in the security means of the mobile terminal and when the event is proposed to said mobile terminal, the message is decrypted, the credit (if any) is processed and the key (CW) for the event is returned to the mobile terminal.
It is to be noted that on numerous occasions the user cannot receive the content for technical reasons (no reception) or that the user simply forgets to make the necessary arrangements.
Another aspect is the security of the transmitted message. In fact, this message can be transmitted several days in advance, which offers third parties many possibilities of breaking the encryption of this message to extract the right or the keys and thus to have access to the content without paying the related fee.